1/6 rc stuart tank

[mrtankman]

help
i am trying to run my 1/6 stuart on the heng longs tk6 and tk7.1s boards! all keep malfunctioning after a couple of mins! i am using 2 x graupner 600bb motors each 17amp draw rating! i use a lucas 12v 7 amp battery! do i need a 30amp battery???? any ideas??? cheers guys

[mrtankman]

help
forgot to mention the graupner motors are 12v each! md

[Ecam]

My hunch is that is too much power for those boards. Not sure what the larger scale crowd runs with those batteries and motors, but I'm sure that little HL module can't handle 1t. I am sure your answer will be along shortly.

[tankme]

During normal operation a motor can draw very few amps, but during a heavy load or a stall condition a motor can draw A LOT of amps. Sometimes that is 4 or 5 times it's nominal draw. At this point there is no way to tell where your electronics are failing. The HL 7.1 says it peaks at 180A...no way...no how...not ever going to be capable of that. Not sure where HL got that rating, but it is BS for a controller of it's size. If you take the rated amps printed on the board and multiply them by 12V which the board is supposed to be able to handle, that gives you 2160 watts for power handling. Once again...no way...no how...not from this board. A 2000W motor is VERY LARGE. I believe the original motors in the M5 were 550s?

I have some very expensive Vantec and IMI Victor ESCs that are only rated at 60A and 80A continuous and the MOSFETs (metal oxide semiconductor field effect transistors) are much larger than anything in a HL board. Those ESCs have overcurrent protection up to 120A for a couple of seconds before burning out. For a larger 1/6th scale tank I use fuses between the motors and my ESCs to ensure they never exceed the rating of my ESCs and burn them out. So for my 60A Victors I use a 50A fuse as my 1/6th Sturmtiger actually ate some 30A fuses earlier in my testing when the vehicle was stalled. My guess is that your motors are drawing too much current from the built in ESC on the HL and blowing out the transistors.

What is the actual rating for these HL controllers? Who knows, but it is no where near what they say on the outside. My suggestion would be to buy some 12A fuses and holders and put them inline with the positive side of your motors. If you blow those fuses while using your Stuart then you are probably exceeding the capacity of the HL controller.

[tankme]

You can see from the pic below of my 1/6th KV-2 that I actually use breakers rather than fuses after determining suitable amperage ratings. I also have a main breaker to my batteries for a little extra protection. There is a cover that goes over the distribution block to keep fingers out of it. My motors are rated for 450W@24V. They are capable of over 100A of current at stall, but my KV-2 weighs like 150lbs as the tracks are all steel.